A multinational study of the factorial structure and other characteristics of the Dartmouth COOP Functional Health Assessment Charts/WONCA.
BACKGROUND
The 'Dartmouth COOP Functional Health Assessment Charts/WONCA' constitute a relatively new derived instrument for assessing health status that is specifically intended for use in primary care on a world-wide basis. It needs further validation in its special area of use.


OBJECTIVE
Over a range of countries, social backgrounds and case mixes, our aim was (i) to examine the factorial structure of the instrument; (ii) to explore how well it was understood; (iii) to check its acceptability; and (iv) to assess the value of the pictures on the charts.


METHODS
The charts themselves, accompanied by a short questionnaire about the charts, were administered to 1719 patients at eight varied types of treatment centre in Canada, Japan, Nepal and Spain. The responses to the instrument were subjected to standard factor analysis and a special Q-type principal components analysis. The responses to direct questions about the charts were compared with the answers to open-ended questions.


RESULTS
Factor analysis suggested a shared factorial pattern for all sites, with the first two factors accounting for 88.5% of the variability in correlations between the charts across the sites. The individual questions were understood by most patients, but a substantial minority did not appear to grasp the underlying purpose of the instrument. The instrument was well accepted. The pictures were considered to be helpful by most respondents, especially those at the Nepal sites. The variability in the scores for the individual charts across sites was less than expected and not always in the expected direction.


CONCLUSIONS
The COOP/WONCA system continues to show promise, but needs more validation.
Westbury
R C
RC
Rogers
T B
TB
Briggs
T E
TE
Allison
D J
DJ
Gérvas
J
J
Shigemoto
H
H
Elford
W
W
D002170:Canada; D003431:Cross-Cultural Comparison; D005163:Factor Analysis, Statistical; D006305:Health Status Indicators; D006801:Humans; D007564:Japan; D009390:Nepal; D011320:Primary Health Care; D015203:Reproducibility of Results; D013030:Spain; D011795:Surveys and Questionnaires / Q000592:standards*